1. Field of the Invention
The present invention relates to methods, systems, and apparatus for lysing and processing algae to extract lipids, proteins, carbohydrates, metabolites, and/or other cellular components. In particular, the invention is a method, system, and apparatus for extracting lipids and other cellular components from algae in which an algae cell lysate comprising an ionic liquid is used to lyse algae.
2. Description of Related Art
US 2009/0234146 A1 discloses a method for the direct transesterification and extraction of biolipids from biomass, including plants, yeast, and algae. The method requires contacting the biomass with a cosolvent comprising an ionic liquid and a polar covalent molecule. The method discloses an example of processing algae cells by suspending freeze dried algae cells in water and mixing the suspension with a cosolvent comprising 46% ionic liquid and 54% methanol by weight. The method requires a cosolvent system containing both ionic liquid and polar covalent solvent to lyse cells and for the formation of separate hydrophilic and hydrophobic phases. The method involves drying algae cells to a powder before suspending the cells in water before lysis.
US 2011/0130551 A1 discloses a one-step process for the lysis of microalgae cells by 1-butyl-3-methylimidazolium chloride (BMIM Cl) and the separation of cellular lipids for use in biofuel production. U.S. Pat. No. 8,211,307 discloses a method for processing algae in which a hydrophilic ionic liquid is used to lyse algae cells, separate hydrophobic and hydrophilic phases are formed, and the two phases are separated. The hydrophilic ionic liquid may be recovered for reuse by adding a salt to the isolated hydrophilic phase to form separate aqueous salt and ionic liquid phases. US 2011/0076748 A1 discloses a method for extracting material from algae cells in which algae cells are contacted with a pure ionic liquid or an active ionic liquid comprising at least 65% ionic liquid. US 2011/0192793 A1 discloses a method for processing algae cells by mixing wet algae cells with a hydrophilic ionic liquid to form a cell lysate and salting out the cell lysate to form separate hydrophobic, ionic liquid, and aqueous salt solution phases.
The aforementioned processes are capable of lysing and processing algae cells using an ionic liquid and recycling the ionic liquid after it is used to lyse cells. Ionic liquids, having lower vapor pressures than volatile organic solvents used for chemical cell lysis, are generally safer to transport and use. Ionic liquids, however, are much more expensive than organic solvents and must therefore be recycled with minimal losses. The process of recycling ionic liquids consumes time and energy and may involve heating the ionic liquid to remove water. Repeatedly heating ionic liquids during recycling may gradually cause some ionic liquids to decompose and/or limit their capacity to lyse cells. Salting out of ionic liquids consumes time and materials and phosphate salts that are effective for salting-out ionic liquids can be damaging to the environment. Accordingly, there is a need for further improved methods and systems for processing algae, and other biomass, that reduce the time, energy, temperature, and materials required for purifying the ionic liquid before reuse.
The formation of separate hydrophobic and hydrophilic phases may be difficult when the volumes of lipid extracted are relatively small compared to the total volume of cell lysate. Accordingly, there is a need for methods and systems for extracting lipid from algae, and other biomass, that improve phase separation.
Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination, by providing a system, a method, and a computer-readable medium for processing algae and other biomass, according to the appended patent claims.